Effect Of Pretreatment Research Articles

Effect of Ultrasonic Pre-Treatment on the Reverse Flotation of Kaolinite From Bauxite

ABSTRACT Cationic reverse flotation of kaolinite from bauxite is an alternative to adequate high silica bauxites to the specifications of the Bayer process. However, the presence of clay minerals influences the slurries rheology decreasing the flotation performance. The objective of this work was to investigate the use of ultrasonic pre-treatment on kaolinite flotation and contrast it with the traditionally used chemical dispersant. Two bauxite samples were characterized in terms of chemical and mineralogical composition, as well as particle size distribution. Flotation was accomplished after conditioning with sodium polyacrylate and/or pre-treatment in ultrasound. Determinations of viscosity, sedimentation yield, and screening followed by the analysis of available alumina and reactive silica were also conducted. By increasing the concentration of solids to more than 20 wt.%, the slurry behavior changed from a Newtonian to a non-Newtonian behavior, the viscosity increased, and the flotation performance decreased. The use of chemical dispersant and ultrasonic pre-treatment increased the flotation performance. The ultrasound had a more marked effect in slurries with higher concentrations of solids. This result is related to the synergic effect of particle dispersion and reduction of the slime coating promoted by kaolinite onto gibbsite particles.

Protein and Polysaccharide Recovery from Shrimp Wastes by Natural Deep Eutectic Solvent Mediated Subcritical Water Hydrolysis for Biodegradable Film.

Environmental pollution is a significant problem due to the improper disposal of plastics and shrimp shells outdoors. Therefore, the synthesis of biodegradable film from waste materials is highly important. The novelty of this research lies in the extraction of protein hydrolysates and chitosan from shrimp shells, as well as the fabrication of biodegradable film from these materials. In this study, the composite films were produced using the solution casting method. Moreover, the combined effect of ultrasound pretreatments (UPT) and natural deep eutectic solvents (NADES) was investigated as extraction media, to determine their potential impact on shrimp waste subcritical water hydrolysis (SWH). Shrimp shells were submitted to UPT in NADES solution, followed by SWH at different temperatures ranging from 150 to 230°C under 3MPa for 20min. Then, the physiochemical properties and bioactivities of the hydrolysates were assessed to determine their suitability for use in biodegradable packaging films. Additionally, the physiochemical properties and bioactivities of the resulting hydrolysates were also analyzed. The highest amount of protein (391.96 ± 0.48mg BSA/g) was obtained at 190°C/UPT/NADES, and the average molecular size of the protein molecules was less than 1000Da with different kinds of peptide. Overall, combined UPT and SWH treatments yielded higher antioxidant activity levels than individual treatments. Finally, the application of composite films was evaluated by wrapping fish samples and assessing their lipid oxidation. The use of higher concentrations of protein hydrolysates significantly delayed changes in the samples, thereby demonstrating the film's applicability.

L-theanine abates oxidative stress and mitochondrial dysfunction in myocardial ischemia-reperfusion injury by positively regulating the antioxidant response

L-theanine (L-THE), a non-protein amino acid isolated from Camelia sinensis, has antioxidant properties that could prevent oxidative damage and mitochondrial dysfunction generated by myocardial ischemia and reperfusion (I/R) injury. The present study aimed to identify the effects of pretreatment with L-THE in rat hearts undergoing I/R. Wistar rats received vehicle or 250 mg/Kg L-THE intragastrically for 10 days. On day 11, hearts were removed under anesthesia and exposed to I/R injury in the Langendorff system. Measurement of left ventricular developed pressure and heart rate ex vivo demonstrates that L-THE prevents I/R-induced loss of cardiac function. Consequently, the infarct size of hearts subjected to I/R was significantly decreased when L-THE was administered. L-THE also mitigated I/R-induced oxidative injury in cardiac tissue by decreasing reactive oxygen species and malondialdehyde levels, while increasing the activity of antioxidant enzymes, SOD and CAT. Additionally, L-THE prevents oxidative phosphorylation breakdown and loss of inner mitochondrial membrane potential caused by I/R, restoring oxygen consumption levels, increasing respiratory control and phosphorylation efficiency, as well as buffering calcium overload. Finally, L-THE modifies the expression of genes involved in the antioxidant response through the overexpression of SOD1, SOD2 and CAT; as well as the transcriptional factors PPARα and Nrf2 in hearts undergoing I/R. In conclusion, L-THE confers cardioprotection against I/R injury by preventing oxidative stress, protecting mitochondrial function, and promoting overexpression of antioxidant genes. More studies are needed to place L-THE at the forefront of cardiovascular research and recommend its therapeutic use.

Sustainable wheat straw pretreatment process by self-produced and cyclical crude lactic acid

The purpose of this study was to investigate an environmentally friendly and recyclable pretreatment approach that would enhance the enzymatic digestibility of wheat straw. Wheat straw was pretreated using self-produced crude lactic acid obtained from enzymatic hydrolysate fermentation by Bacillus coagulans. Experimentally, crude lactic acid at low concentration could achieve a pretreatment effect comparable to that of commercial lactic acid. After pretreatment at 180 °C for 60 min with 2.0 % crude lactic acid, hemicellulose could be effectively separated and high recovery of cellulose was ensured, achieving cellulose recovery rate of 95.5 % and hemicellulose removal rate of 92.7 %. Excellent enzymatic hydrolysis was accomplished with a glucose yield of 99.7 %. Moreover, the crude lactic acid demonstrated acceptable pretreatment and enzymatic hydrolysis performance even after three repeated cycles. This not only effectively utilizes the pretreatment solution, but also offers insights into biomass pretreatment using other fermentable acids.

Effect of Mechanical-Chemical Pretreatment at Room Temperature on Properties of Cellulose and Cellulose Solution

Effect of Mechanical-Chemical Pretreatment at Room Temperature on Properties of Cellulose and Cellulose Solution

Pretreatment with interleukin-15 attenuates inflammation and apoptosis by inhibiting NF-κB signaling in sepsis-induced myocardial dysfunction.

Sepsis-induced myocardial dysfunction (SIMD) is associated with poor prognosis and increased mortality in patients with sepsis. Cytokines are important regulators of both the initiation and progression of sepsis. Interleukin-15 (IL-15), a pro-inflammatory cytokine, has been linked to protective effects against myocardial infarction and myocarditis. However, the role of IL-15 in SIMD remains unclear. We established a mouse model of SIMD via cecal ligation puncture (CLP) surgery and a cell model of myocardial injury via lipopolysaccharide (LPS) stimulation. IL-15 expression was prominently upregulated in septic hearts as well as cardiomyocytes challenged with LPS. IL-15 pretreatment attenuated cardiac inflammation and cell apoptosis and improved cardiac function in the CLP model. Similar cardioprotective effects of IL-15 pretreatment were observed in vitro. As expected, IL-15 knockdown had the opposite effect on LPS-stimulated cardiomyocytes. Mechanistically, we found that IL-15 pretreatment reduced the expression of the pro-apoptotic proteins cleaved caspase-3 and Bax and upregulated the anti-apoptotic protein Bcl-2. RNA sequencing and Western blotting further confirmed that IL-15 pretreatment suppressed the activation of nuclear factor kappa B (NF-κB) signaling in mice with sepsis. Besides, the addition of NF-κB inhibitor can significantly attenuate cardiomyocyte apoptosis compared to the control findings. Our results suggest that IL-15 pretreatment attenuated the cardiac inflammatory responses and reduced cardiomyocyte apoptosis by partially inhibiting NF-κB signaling in vivo and in vitro, thereby improving cardiac function in mice with sepsis. These findings highlight a promising therapeutic strategy for SIMD.

Insight into Low-Temperature One-Step Biopreparation and Natural Dyeing of Cotton as an Environmentally Benign Route

AbstractThe goal of this study is to present an environmentally benign route for cotton fabric and investigate the effect of different pretreatments in natural dyeing. In this context, conventional alkaline scouring, conventional hydrogen peroxide bleaching, low-temperature one-step biopreparation processes, namely enzymatic scouring (alkaline pectinase and alkaline pectinase-neutral cellulase combination) at 55 °C and enzyme-bleaching agent (hydrogen peroxide/sodium percarbonate/sodium perborate)-activator agent (TAED) combinations at 65 °C were applied to 100% cotton knitted fabric. The use of agricultural waste and eco-friendly mordants was preferred in natural dyeing. For this purpose, pretreated fabrics were dyed with the outer green shell of almond fruit extracts and a low amount of 0.4 g/L metal mordants (alum and iron(II) sulfate) in accordance with the simultaneous mordanting method. The dyeing properties of bio- and conventionally prepared cotton fabrics were examined in terms of colorimetric data (K/S, CIELa*b*C*h°) and wash fastness compared with water absorbency, whiteness, weight loss, pectin removal, and type of mordant. Excellent wash fastness values were achieved regardless of the type of pretreatment. Low-temperature one-step biopreparation can be a good substitute for conventional scouring and bleaching processes. Since different results can be achieved, it is essential to determine and evaluate all bioprocess conditions depending on the end-use characteristics of the textile (e.g. whether it will be white or dyed/printed, its color and lightness/darkness) at the laboratory and industrial scale applications.

Effects of tea polyphenols pretreatment of kanamycin mycelial residue on subsequent aerobic composting: Improvements in antibiotic resistance control

Our previous research has demonstrated the efficient removal of residual kanamycin in kanamycin mycelial residue (KMR) through abiotic humification with tea polyphenols (TP). This study aims to investigate the impact of TP pretreatment on the subsequent composting of KMR, focusing on composting quality, kanamycin residue, and antibiotic resistance. The physicochemical results indicated that TP pretreatment not only showed no adverse impact on the composting, but exhibited the potential to enhance humification according to the results of the three-dimensional fluorescence results. Moreover, a 22.6 % lower kanamycin content (0.24 mg/kg) was observed in the final fertilizer product from TP pretreatment, with approximately 6.9 times the total relative abundance of target antibiotic resistance genes (ARGs) reduced. The Proteobacteria, Firmicutes and Actinobacteria were the primary potential hosts for ARGs and mobile genetic elements (MGEs). Overall, TP pretreatment appears to be a promising approach for achieving a safer resource utilization of KMR through composting.

Sea Buckthorn Polysaccharide Ameliorates Colitis

Ulcerative colitis (UC) is characterized by chronic inflammation and ulceration of the intestinal inner lining, resulting in various symptoms. Sea buckthorn berries contain a bioactive compound known as sea buckthorn polysaccharide (SBP). However, the precise mechanisms underlying the impact of SBP on UC remain unclear. In this study, we investigated the effects of pretreatment with SBP on colitis induced by DSS. Our findings demonstrate that SBP pretreatment effectively reduces inflammation, oxidative stress, and intestinal barrier damage associated with colitis. To further elucidate the role of SBP-modulated gut microbiota in UC, we performed fecal microbiota transplantation (FMT) on DSS-treated mice. The microbiota from SBP-treated mice exhibits notable anti-inflammatory and antioxidant effects, improves colonic barrier integrity, and increases the abundance of beneficial bacteria, as well as enhancing SCFA production. Collectively, these results strongly indicate that SBP-mediated amelioration of colitis is attributed to its impact on the gut microbiota, particularly through the promotion of SCFA-producing bacteria and subsequent elevation of SCFA levels. This study provides compelling evidence supporting the efficacy of pre-emptive SBP supplementation in alleviating colitis symptoms by modulating the gut microbiota, thereby offering novel insights into the potential of SBP as a regulator of the gut microbiota for colitis relief.

Pro-inflammatory interactions of streptolysin O toxin with human neutrophils in vitro

The recent global resurgence of severe infections caused by the Group A streptococcus (GAS) pathogen, Streptococcus pyogenes, has focused attention on this microbial pathogen, which produces an array of virulence factors, such as the pore-forming toxin, streptolysin O (SOT). Importantly, the interactions of SOT with human neutrophils (PMN), are not well understood. The current study was designed to investigate the effects of pretreatment of isolated human PMN with purified SOT on several pro-inflammatory activities, including generation of reactive oxygen species (ROS), degranulation (elastase release), influx of extracellular calcium (Ca2+) and release of extracellular DNA (NETosis), using chemiluminescence, spectrophotometric and fluorimetric procedures, respectively. Exposure of PMN to SOT alone caused modest production of ROS and elastase release, while pretreatment with the toxin caused significant augmentation of chemoattractant (fMLP)-activated ROS generation and release of elastase by activated PMN. These effects of treatment of PMN with SOT were associated with both a marked and sustained elevation of cytosolic Ca2+concentrations and significant increases in the concentrations of extracellular DNA, indicative of NETosis. The current study has identified a potential role for SOT in augmenting the Ca2+-dependent pro-inflammatory interactions of PMN, which, if operative in a clinical setting, may contribute to hyper-activation of PMN and GAS-mediated tissue injury.

Enhancing the Strength and the Environmental Performance of Concrete with Pre-Treated Crumb Rubber and Micro-Silica

Dumped non-biodegradable tires present a significant environmental threat, with overflowing landfills and associated health risks highlighting the urgency of tire waste disposal. Current disposal methods, such as stacking tires in open spaces, exacerbate the problem. The large-scale recycling of tire rubber waste offers environmental benefits. This study examines the effects of pre-treatment using NaOH and micro-silica as a mineral admixture on the mechanical strength of crumb rubber concrete (CRC) with partial replacement of natural sand. Samples of M20 and M30 grade were prepared with varying levels of crumb rubber (CR) replacement and evaluated at 28 days. CRC prepared with pre-treated NaOH solution and micro-silica showed improved workability and strength compared to conventional concrete and untreated CRC, with the highest strength observed for 5% CR replacement using micro-silica. Predictive models and micro-structural analysis validated these findings. Life Cycle Assessment (LCA) using OpenLCA v2.10 software and the ecoinvent database revealed that incorporating micro-silica into CRC did not significantly increase environmental impacts, compared to conventional concrete across different mixes.

Comparison of effects of carbocation scavengers assisted acid pretreatment on improving enzymatic digestibility of masson pine and poplar

To investigate the disparate effects of carbocation scavengers on promoting the enzymatic hydrolysis of softwood and hardwood, five carbocation scavengers were supplemented during acid pretreatment of masson pine and poplar in this study, including 2-naphthol (2 N), 2-naphthol-7-sulfonate (NS), p-hydroxybenzoic acid (PB), vanillic acid (VA) and syringic acid (SA). The results showed that naphthols (2 N and NS) with only one nucleophilic site enhanced delignification and enzymatic hydrolysis more significantly than the monophenols with several reactive sites. Adding 2 N and NS increased the hydrolysis yield of acid-pretreated masson pine (AM) from 14.87% to 20.58% and 35.52%, respectively. Correspondingly, the hydrolysis yield of acid-pretreated poplar (AP) improved from 56.54% to 80.47% and 86.9%, respectively. Moreover, as pretreatment severity increased, the enzymatic digestibility of AM and AP first increased and then decreased. However, the naphthols modification retarded this decline, especially for the enzymatic hydrolysis of pretreated poplar. The structure of carbocation scavengers and the lignin unit composition jointly determined the improvement on enzymatic hydrolysis of woody biomass by carbocation scavengers. Furthermore, the naphthols promoted the enzymatic hydrolysis mainly by alleviating enzyme non-productive binding.

Effect of ultrasound-assisted xylanase pretreatment on the soluble substances of poplar wood and its model construction

Effect of ultrasound-assisted xylanase pretreatment on the soluble substances of poplar wood and its model construction

Effects of Cold Plasma Pretreatment and Cultivar on the Drying Characteristics, Biochemical, and Bioactive Compounds of 'Tropica' and 'Keitt'Mangoes

Abstract Purpose Mango is a well-known and widely consumed fruit for its savoury taste and nutritional benefits. However, a lack of efficient postharvest handling prior to its storage could gradually lead to undesirable changes that cause postharvest losses. Dehydration techniques such as hot air drying have shown to minimize the water activity thereby preserving fruit shelf-life. Pretreatment prior drying has the advantage of shortening the drying times, consuming less energy, substituting chemical use, and maintaining the quality attributes of agricultural products. Therefore, the main purpose of this research is to assess the application of cold plasma (CP) as a pretreatment step before drying ‘Tropica’ and ‘Keitt’ mango slices. Methods The effect of low-pressure cold plasma pretreatment duration (5 and 10 min) and mango cultivar differences was investigated on drying properties, quality attributes, and microbial load. Thin layer mathematical models fitted were fitted to the data collected to describe the drying behaviour. Results Mango cultivars behaved differently during drying as ‘Keitt’ samples had a shorter drying time (10 h) compared to ‘Tropica’ samples (12 h). Logarithmic model best predicted the drying behaviour with a determination coefficient R2 of 0.99 and RMSE of 0.0664. Change in bioactive compounds, antioxidant capacity, and microbial load of ‘Tropica’ and ‘Keitt’ mango slices were significantly affected by CP pretreatment and drying (p < 0.05). Conclusion The findings of this study showed that cold plasma improved the drying rate of dried mango slices. Total phenolic and antioxidant activity were improved with cold plasma treatment of 10 min. In summary, cold plasma improves drying kinetics and the quality attributes of mango fruit.

Effects of composition and pre-treatment on the physical and mechanical properties of pellets of orange juice waste

Effects of composition and pre-treatment on the physical and mechanical properties of pellets of orange juice waste

Effect of electron beam irradiation pretreatment and different fatty acid types on the formation, structural characteristics and functional properties of starch-lipid complexes

The effects of different electron beam irradiation doses (2, 4, 8 KGy) and various types of fatty acids (lauric acid, stearic acid, and oleic acid) on the formation, structure, physicochemical properties, and digestibility of starch-lipid complex were investigated. The complexing index of the complexes was higher than 85 %, indicating that the three fatty acids could easily form complexes with starch. With the increase of electron beam irradiation dose, the complexing index increased first and then decreased. The highest complexing index was lauric acid (97.12 %), stearic acid (96.80 %), and oleic acid (97.51 %) at 2 KGy radiation dose, respectively. Moreover, the microstructure, crystal structure, thermal stability, rheological properties, and starch solubility were analyzed. In vitro digestibility tests showed that adding fatty acids could reduce the content of hydrolyzed starch, among which the resistant starch content of the starch-oleic acid complex was the highest (54.26 %). The lower dose of electron beam irradiation could decrease the digestibility of starch and increase the content of resistant starch.

Effect of ultrasonic pretreatment on the structure and emulsion stability of epigallocatechin-3-gallate and rice bran protein complex

To enhance the emulsion stability of RBP, the mixed solution of epigallocatechin-3-gallate (EGCG) and rice bran protein (RBP) was pretreated by increasing ultrasonic power (200–500 W). Ultrasonic pretreatment decreased the α-helix/β-sheet ratio (P < 0.05), and caused red-shift absorption peaks of intrinsic fluorescence and UV absorption spectroscopy of EGCG-RBP complex. With increasing ultrasonic power, combined phenol content, particle size, absolute value of ζ-potential, free –SH content, and surface hydrophobicity of EGCG-RBP complex initially rose, and subsequently dropped (P < 0.05). Compared with the EGCG-RBP complex without ultrasonic pretreatment, emulsifying activity index increased from 37.68 m2/g to 42.51 m2/g, and emulsion stability index increased from 123.00 min to 326.43 min as ultrasonic power was 425 W. The centrifugal stability constant, emulsion separation rate, and emulsion particle size initially dropped, and subsequently rose with increasing ultrasonic power. The emulsion stability of EGCG-RBP complex was correlated with particle size, absolute value of ζ-potential, α-helix/β-sheet ratio, free –SH content, and surface hydrophobicity (P < 0.05). Overall, ultrasonic pretreatment enhanced the EGCG-RBP interaction by regulating the absolute value of ζ-potential, flexibility and surface hydrophobicity of EGCG-RBP complex, thus improving emulsion stability, which provided a theoretical foundation for expanding the application of RBP in foodstuffs.

Synergistic effect of two bacterial strains promoting anaerobic digestion of rice straw to produce methane

A large amount of agricultural waste causes global environmental pollution. Biogas production by microbial pretreatment is an important way to utilize agricultural waste resources. In this study, Sporocytophaga CG-1 (A, cellulolytic strain) was co-cultured with Bacillus clausii HP-1 (B, non-cellulolytic strain) to analyze the effect of pretreatment of rice straw on methanogenic capacity of anaerobic digestion (AD). The results showed that weight loss rate of filter paper of co-culture combination is 53.38%, which is 29.37% higher than that of A. The synergistic effect of B on A can promote its degradation of cellulose. The cumulative methane production rate of the co-culture combination was the highest (93.04 mL/g VS substrate), which was significantly higher than that of A, B and the control group (82.38, 67.28 and 67.70 mL/g VS substrate). Auxiliary bacteria can improve cellulose degradation rate by promoting secondary product metabolism. These results provide data support for the application of co-culture strategies in the field of anaerobic digestion practices.

PTH treatment before cyclic joint loading improves cartilage health and attenuates load-induced osteoarthritis development in mice.

Osteoarthritis (OA) treatment is limited by the lack of effective nonsurgical interventions to slow disease progression. Here, we examined the contributions of the subchondral bone properties to OA development. We used parathyroid hormone (PTH) to modulate bone mass before OA initiation and alendronate (ALN) to inhibit bone remodeling during OA progression. We examined the spatiotemporal progression of joint damage by combining histopathological and transcriptomic analyses across joint tissues. The additive effect of PTH pretreatment before OA initiation and ALN treatment during OA progression most effectively attenuated load-induced OA pathology. Individually, PTH directly improved cartilage health and slowed the development of cartilage damage, whereas ALN primarily attenuated subchondral bone changes associated with OA progression. Joint damage reflected early transcriptomic changes. With both treatments, the structural changes were associated with early modulation of immunoregulation and immunoresponse pathways that may contribute to disease mechanisms. Overall, our results demonstrate the potential of subchondral bone-modifying therapies to slow the progression of OA.

Effects of feedstock pretreatment and binder selection on briquette characterization

Effects of feedstock pretreatment and binder selection on briquette characterization